Engine control for free-piston units



Nov. 9, 1948. A. KALITINSKY 2,453,516

ENGINE CONTROL FOR FREE-PISTON UNITS Filed Nov. 6, 1944 INVENTOR MmKMQM cause changes in the gas.

Eatented Nov. 9, 19.48

ange ic UNITED STATES PATENT. OFFICE CONTROL FOR FREE-PISTON UNITS Conn, a corporation Application Eagievilie, Conn., Corporation,

of Delaware November 6, 1944, Serial No. 562.251

assignor to East Hartford,

4 Claims- (Cl. 230-56) i ternal combustion engines.

The variations in exhaust pressure in an internal combustion engine may be used to indicate the operation of the engine or may be used to the engine operation. If the control actuated by the exhaustipressure is connected directly to the exhaust d ct, however the control may be damaged by theg action of the ingredients in the exhaust gas. {A feature of the invention is the removal of theexhaust gas from the controls so that they will not be aflected by If the engine is superchar ed or scavenged the supercharged or scavenged air has ahigher pressure than the exhaust A feature of the inart of this higher vention is the use of a pressure air tween the controls and the exhaust.

In many instances the compressor which supplies the super 'or scavengi g air is an integral part of the engine unit. as in free-piston engine and compressor units, in which the compressors supply scavenge air to the engine and may be connected directly to .the scavenge ports. The scavenge pressure from the compressor is necessarily greater than the exhaust pressure to permit eiiective scavenging of the engine cylinder. A feature of this invention isthe bleeding of the scavenge air from the compressors into the connection between the exhaust actuated controls and the exhaust duct. a I

Since the pistons o! a tree-piston unit have a variable stroke the operation of the unit is afiected by changes in exhaust pressures which may 5 be compensated for by changing certain of the operating characteristics such as, the pressurein the air springs. Continuous indication of exhaust pressure is desirable in permitting control invention is, the adaptation of the control scavenging device to this type of unit.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an em- 45- bodiment of the invention.

The single figure is a sectional view through the free-piston unit with the scavenging system for the controls shown diagrammatically.

The unit shown includes an engine cylinder having reciprocating pistons l2 and I4 to which compressorpistons It and It in cylinders 20 and 22 are integrally connected. Sleeves II and 2 attached to the compressor pistons complete the reciprocating piston assemblies. The sleeves in for scaven the connection bei through which air combination with stationary pistons 2a and a I iorm air spring cylinders.

The piston assembliesare moved apart by the burning of fuel injected into engine cylinder ill through one or more nozzles. Air compressed in the air spring cylinders on the power stroke returns the piston assemblies. The assemblies are always maintained at equal distances from the center of the engine cylinder by a linkage which may include rods 33 extending from the piston assemblies and having rack teeth thereon engaging with an intermeshing pinion. not shown.

Intake manifold 34 conducts air tov intake valves 36 in the heads of the compressor cylinders I alternately enters opposite ends of the compressor cylinders. The compressed air leaves the cylinders through discharge valves 38 also located at opposite pressor cylinder and passes into a scavenge manifold Ill. Compressed air from the scavenge manifold enters engine ports 42 and it which are uncovered by pistons 12 and M at the end of the power stroke, thereby permitting air to be blown through the engine cylinder. Gas and air in the engine cylinders are discharged through exhaust ports 46 and 48 into exhaust rings to a manifold 52 which may be connected to an exhaust collector, not shown.

For indicating changes in the exhaust pressure 0 a duct 54 which is connected to the exhaust manifor example,

of the unit. A feature of this 40- fold connects withpressure indicating or pressure responsive devices such as the cylinders 56 in which spring pressed plungers 58 are slidable. Theprojecting rods 60 on the plungers may be connected to indicating apparatus or to control devices by which the operation of the unit may be changed in response to the changes in exhaust pressure.

With exhaust gas entering the duct 51 the impurities or the ingredients of the gas may cause corrosion oi the cylindersor may deposit sediment in the cylinders affecting the operation of II to enough to maintain a slow these devices, and the devices may also be affected by the high temperature of the exhaust gases. To prevent this, a duct 62 which communicates with the scavenge ir enters the duct 5 at a point spaced somewhat from the connection of the duct 54 with exhaust manifold 52. A control valve Bl provides a restriction in duct 82 and limits the pressure and amount of scavenge air entering duct it so that the quantity or air is flow of air from duct 6: into exhaust manifold 52. Thisslow flow of air does not materially aflect the pressure in duct to 'II. which remains substantially equal to the exends of the com-v 50 connected that of duct 54 sarily higher in necting duct being closed at tively reduces the scavenging air pressure reaching duct 94 to an amount only very slightly above to assure a slow flow or air from duct 92 through duct-IQ mm the exhaust duct 52.

. haust pressure: The restriction or valve 6 eilec- I I 4 tingairiromthecom duet between said pressure-actuated means and As will be apparent. the scavenge air is--necesthis higher pressure assures a continuous flow oi air at a sumcient pressure diflerential to prevent pressure than the exhaust 85 a in order that the engine may be scavenged,

It is to he understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. An engine-and -com pressor unit including an engine having an exhaust duct. a compressor driven by the engineand providing air under pressure for scavenging the engine, pressure responsive control means connected to the exhaust duct and actuated by exhaust pressure, and. a connection between said means and the exhaust duct, in combination with means for admitting scavenge air from said compressor to the connec= tion between said means and the exhaust duet, including a restriction for limiting the quantity and pressure of scavenge air entering said connection. r g

2. An engine-and-compressor unit including an engine having an exhaust duct, a compressor driven by the engine and providing air for seavenging the engine, pressure responsive control means connected to the exhaust duct and actuated by exhaust pressure, and a connecting duct from said means to the exhaust duct, said conthe end remote from its connection to the exhaust duct, whereby no substantial flow of gas takes place in the duct. in combination with means nectineduct.

said exhaust and throttling means tor reducing the pressure of the scavenge air entering the cons. A tree-piston unit including an enelne cyl- "inder, a compressor cylindena pistonassembly fitting in said cylinders, an exhaust duct to: said engine, and a connection for scavenge air from enge air connection for admitting air from said scavenge air connection to said conduit whereby exhaust gas is prevented from direct access to annnaw NSKY.

. lannannnons T The following references are oi record in t the of this patent:

unrran s'rsrms PATENTS Number Name 7 Date 1,757,317 Pescara May 6, 1930 1,930,788 Witkiewicz et al Oct 17, 1933 2,116,921 Steiner May 3, 1938 2,147,935 Steiner Feb. 21,1939 2,163,767 Steiner June 27, 1939 2,200,892 Pescara May 14, 1940 Steiner 2,248,701 June 24, 19 41 to the connecting means and the a piston assembly 

